Pittsburgh Modular Lopass Gate

The Pittsburgh Modular Lopass Gate module is a new take on a classic. Our intention was not to clone but to reengineer and expand on the original circuit. Our module includes an amazing new self-oscillating resonance circuit and a quieter vactrol based VCA circuit with true unity gain. Voltage control of the module is handled using an invertible, attenuated input and ping input. The ping input takes any gate or square wave and converts it into a very tight trigger used to ping the vactrol.

In lopass filter mode, frequency sweeps are warm and buttery and resonance is smooth and controlled until it gets near self oscillation. At this point the Pittsburgh Modular LPG module turns into a shouting beast. High resonance creates an edgier, shattered, more direct sound. It never loses control but is always teetering on the edge. Having both the smooth and snarling responses available creates a filter that is perfect for almost any situation.

In VCA mode, we worked very hard to reduce the bleed associated with most lopass gate circuits without resorting to tricks like adding an a traditional VCA after the vactrol circuit. After considerable effort, we succeeded in creating a vactrol based VCA that is identical or better in performance to our 2164 based Dual VCA module.

All the work we did on the filter and VCA come together with the lopass gate mode. The buttery warmth of the filter teams with the best attributes of the vactrol based VCA to create an impressive take on the original lopass gate.